Roll a round top boiler, without rollers.

[keidal]

Can anyone suggest how to make a parallel boiler, without using rollers, from flat brass sheet please ? The boiler which I need to make is 43 mm diameter [approx. 4' 6" dia. in Finescale Gauge 1], for an LNER P1 0-6-0 loco. electric motor, not live steam !

I was thinking of using something like 0.5 - 1.0 mm flat brass sheet and I have some lengths of copper tube just a bit smaller in diameter.

Will I have to anneal the brass first, somehow ?

Could I incorporate "Jubillee" clips in the process for example ? I would soft solder the meeting edges

I do have a hefty engineer's vice and basic tools.

I have a 300 mm length of 1 3/4" outside diameter brass tube, with a wall thickness of approximately 1/16" - and I have been quoted £75.00 to turn it down to 43 mm diameter, leaving a short length un-skimmed for a smoke box ! Too expensive to even think about.

I have bought the Isinglass drawing for the loco - an LNER P1 0-6-0, which is only available in 4 mm scale.

Any suggestions would be greatly appreciated.

Keith

[34theletterbetweenB&D]

Have you measured the O.D. of your 300mm length of brass tube? Provided it has a true circular cross section then it might just be near enough as it stands, or you can slit down the length and close up, reducing its diameter slightly. Either way leaving you the simpler task of only rolling  a wrapper for the smokebox.

[MJI]

Slit one section for the boiler and solder the seam.

 

4.5mm removed will take it to about 43mm

 

Use the rest for smokebox

[John Tomlinson]

Forgive the question, but I thought an LNER PI was an eight coupled freight loco designed by Gresley, with something approximating to an A3 boiler?

 

John.

[Steamport Southport]

Yep. It's where using the NER designation is slightly confusing.

 

It's a LNER J25. https://www.lner.info/locos/J/j25.php

 

 

 

Jason

[Barclay]

I've never done anything this big but for smaller loco's in 4mm it's not hard if you anneal it first over a gas flame (cooker!); clean it up with emery paper then roll using brass tube or wooden dowel a fair bit smaller than the size you want. Small ones can be done on your thigh like a cigar but otherwise a soft surface with some give like a cutting mat, or several newspapers in a pile. The mating edges are the hardest part as they don't want to curve so they need more pressure and perhaps a smaller tube to roll with. I would use 10 thou brass in 4mm as it forms quite easily, but you might need it a bit thicker for gauge 1. If you leave it for a few weeks after forming it will regain some of it's former hardness.